Preliminary Study on Dose Distribution in Depth Direction of Soil in Fukushima Prefecture

Abstract

Part of the radioactive material released by the Fukushima Daiichi nuclear power plant accident was deposited on the soil in Fukushima Prefecture. Accumulation of radioactive cesium (Cs) into the soil has been confirmed until now. The distribution of radioactive Cs concentration in the depth direction of the soil was preliminarily investigated in order to clarify the present state of radioactive Cs accumulated in the landfill waste as a part of ensuring the safety of the lives of Fukushima Prefecture residents. A hole with a diameter of 10 cm and a depth up to 1 m was dug in the landfill waste of a final disposal site, and the small amount of landfill waste collected at any depth was quantitatively measured with a germanium semiconductor detector. From the present result, the tendency of the distribution of Cs concentration in the depth direction was clarified for the first time. In addition, it was confirmed that since the depth distribution of the radioactive Cs concentration from the landfill surface was complicated, the tendency of that cannot be expressed using the conventional exponential function model.